No, there are no donation seats in BITS Pilani and all the students are admitted solely on the basis of merit. In fact, my friend told me about an incident here that further proved that BITS Pilani has no donation seats. A very rich person wanted his son to get admitted here and was willing to give a hefty donation for the same. The director of BITS Pilani strongly refused saying they accept students on a merit basis only and no amount of money will get him a seat no matter what.
This brought to light the transparency of admissions here and strengthened my faith in BITS Pilani.